You may dazzle your coworkers with your multitasking chops, but it's probably not doing much for your productivity. Over at Fast Company, our own Gina Trapani continues her Work Smart video series, this time tackling the time-sinks that come along with multitasking.

Doing two things at once, like singing while you take a shower, is not the same as instant messaging while writing a research report. Don't fool yourself into thinking you can multitask jobs that need your full attention. You're not really having a conversation while you write; you're shifting your attention back and forth between the two activities quickly. You're juggling. When you juggle tasks, your work suffers AND takes longer—because switching tasks costs.

Fact is, if we're being honest with ourselves, I think we would all admit to being most productive during those times when we shut everything else off and focus on a single task. We've covered the multitasking-isn't-always-what-it's-cracked-up-to-be angle plentyof timesin thepast, but it's worth the occasional reminder every now and then, especially from a trusted voice.